*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/*
.father{
    width: 400px;
    height: 400px;

    border: 1px dashed black;
    display: flex;!*父元素设置flex属性*!
    justify-content: center;!*水平主轴居中*!
    align-items: center;!*垂直交叉轴居中*!
}
.son{
    width: 50px;
    height: 100px;
    background: pink;
}*/
